短语讲解：

1. They can find out what the subject of the image is, where the image has appeared and about its usage rights.

find out 发现; 使发作; 使受惩罚
例句：I'll find out the address,and ring you back.
我找到地址后再与你通电话。

2. Users can download maps for viewing when they are away from the Internet.

away from 远离; 相距
例句：The sea floor is spreading away from the mid-ocean ridges.
海底正在从大洋中脊扩张开来。

3. In addition to a website, the service is also available as a Google Translate Chrome Extension.

in addition to 除…之外
例句：In addition to light, there are dangerous radiations gi-ven off by the sun.
除了光以外，太阳还发出危险的放射线。

4. Users can add up to five people for a group video chat.

add up 加起来; 总计; 与应有的数量相符
例句：Add up 6,7 and 8 and you'll get 21.
把六、七、八相加，总数是二十一。